High efficiency particulate air rated vacuum bag media and an associated method of production

ABSTRACT

A vacuum bag media and associated method of production, which includes a first layer that includes an expanded polytetrafluoroethylene membrane and at least one second layer that includes a first component having a first melting point and a second component having a second melting point that is higher than the first melting point, wherein the first layer is attached to the at least one second layer. The second layer can include cellulose material, spunbond, nonwoven fabric, and a thermal bond, nonwoven fabric. Attachment of the first layer of material to the at least one second layer of material can occur through thermobonding, e.g., heated gas, infrared heat and heated calender rolls. The application of adhesives and the use of ultrasonic energy can also bond the layers together. Approximately five percent (5%) to fifty percent (50%) of the first component can be selectively melted for superior airflow.

CROSS-REFERENCE TO RELATED APPLICATION

This patent application is a continuation of U.S. patent applicationSer. No. 10/062,063 filed Jan. 31, 2002, now U.S. Pat. No. 6,872,233,which is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

This invention relates to vacuum bag media, and more particularly, to animproved vacuum bag media that is high efficiency particulate air (HEPA)rated and an associated method of production.

Traditional vacuum cleaner bags are produced from specific types ofcellulose paper or combined laminates of cellulose paper andpolypropylene meltblown nonwoven media as well as one hundred percent(100%) synthetic fiber products that include spunbond, nonwoven fibersand meltblown, nonwoven fibers. However, customers are demanding more oftheir vacuum cleaner technology and desire much higher levels offiltration so that dust and other particulate matter are not picked-upby the vacuum cleaner and then transferred into the air right throughthe standard, low efficiency, vacuum cleaner bag under the high pressuresuction of the vacuum cleaner. With this traditional vacuum cleaner bagtechnology, although the visible dirt and debris will no longer bepresent on the carpeting, the fine dust and particles will be projectedinto the surrounding atmosphere of the room and potentially inhaled bythe occupants. For the significant portion of the population that isplagued by allergies, this can be especially problematic. This projecteddust and debris will eventually settle, which will then require dustingor additionally vacuuming for removal. With the low efficiency ratingpresent for a standard vacuum cleaner bag, a significant portion of thedust and debris is constantly being recirculated during each operationof the vacuum cleaner.

Therefore, the trend is for consumers to utilize a HEPA rated baglesscleaner that uses dirt cup technology. HEPA filtration performance istypically achieved by utilizing a primary cleaning cartridge or by asecondary exhaust. HEPA is an acronym that stands for: “High EfficiencyParticulate Air.” One method for determining the HEPA rating is byutilizing Test Method IES-RP-CC021.1, which was developed by theInstitute of Environmental Sciences. This test method defines HEPA as99.97% efficiency when tested with a challenge dust or aerosol that aremade from particles that are 0.3 micron (11.81 microinches) in diameter.Furthermore, the airflow in which the challenge aerosol is presented tothe media is at 5.33 cm./sec. (10.55 ft./min.). Testing is alsoperformed at an increased airflow rate of 8.54 cm./sec. (16.8 ft./min.),which is typical of most vacuum cleaners. The testing of flat sheetmaterial may be performed with a Dioctyl Phthalate (DOP) aerosol on aTSI® 8160 testing device. TSI® is a federally registered trademark ofTSI Incorporated, having a mailing address at P.O. Box 64394, St. Paul,Minn. 55164-0394.

There are literally millions of vacuum cleaners on the market thatrequire the use of a vacuum cleaner bag. Although the filtration ofstandard cellulose paper bags has improved with the combination of asecond layer of electro-statically charged or treated meltblown fiber,which, increases the efficiency rating from fifteen percent (15%) tothirty-five percent (35%) to around eighty percent (80%) to eighty-fivepercent (85%), this meltblown fiber bag media still falls far short ofHEPA filtration status.

The present invention is directed to overcoming one or more of theproblems set forth above.

SUMMARY OF INVENTION

In one aspect of this invention, an improved vacuum bag media isdisclosed. This vacuum bag media includes a first layer having anexpanded polytetrafluoroethylene membrane and at least one second layerthat includes a first component having a first melting point and asecond component having a second melting point that is higher than thefirst melting point, wherein the first layer is attached to the at leastone second layer.

In another aspect of this invention, a process for producing vacuum bagmedia is disclosed. This process includes attaching a first layer havingan expanded polytetrafluoroethylene membrane to at least one secondlayer that includes a first component having a first melting point and asecond component having a second melting point that is higher than thefirst melting point.

These are merely two illustrative aspects of the present invention andshould not be deemed an all-inclusive listing of the innumerable aspectsassociated with the present invention. These and other aspects willbecome apparent to those skilled in the art in light of the followingdisclosure and accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

For a better understanding of the present invention, reference may bemade to the accompanying drawings in which:

FIG. 1 is a perspective view of an upright vacuum cleaner with a vacuumcleaner bag that utilizes vacuum bag media that is constructed inaccordance with the present invention;

FIG. 2 is a perspective view of a vacuum bag media of the presentinvention, having a first layer of material, which includes expandedpolytetrafluoroethylene and a second layer of material, which includes afirst component having a first melting point and a second componenthaving a second melting that is higher than the first melting point;

FIG. 3 is a perspective view of a vacuum bag media of the presentinvention as shown in FIG. 2, which includes another protective layer oftextile material positioned on the other side of the first layer ofexpanded polytetrafluoroethylene material;

FIG. 4 is a perspective view of a bicomponent textile fiber thatincludes both a sheath and a core;

FIG. 5 is a schematic side view of a laminating apparatus forthermobonding the first layer of material with a second layer ofmaterial that includes a heated roll and a water-cooled, nip,compression roll associated with the present invention;

FIG. 6 is a schematic side view of an embossed calendering apparatus forcreating nonwoven fabric utilized with the second layer of materialassociated with the present invention;

FIG. 7 is a graphical representation of air flow versus pressure drop(resistance) for the preferred embodiment that utilizes a first layer ofexpanded polytetrafluoroethylene with a second layer of cellulosematerial that is combined with nonwoven textile fibers;

FIG. 8 is a graphical representation of filtration efficiency versus airflow for the preferred embodiment that utilizes a first layer ofexpanded polytetrafluoroethylene with a second layer of cellulosematerial that is combined with nonwoven textile fibers;

FIG. 9 is a photomicrograph of a preferred embodiment having a secondlayer of material that includes cellulose material combined with abicomponent fiber and embossed bond points that is thermobonded to afirst layer of expanded polytetrafluoroethylene, which is magnified by afactor of five hundred (500×);

FIG. 10 is a photomicrograph of a first alternative embodiment with asecond layer of material that includes a bicomponent, spunbond, nonwovenmaterial with embossed bond points, which is magnified by a factor oftwenty (20×);

FIG. 11 is a photomicrograph of a first alternative embodiment with asecond layer of material that includes a bicomponent, spunbond, nonwovenmaterial with embossed bond points, which is magnified by a factor ofone thousand (1,000×);

FIG. 12 is a photomicrograph of a first alternative embodiment with asecond layer of material that includes a bicomponent, spunbond, nonwovenmaterial with embossed bond points that is thermobonded to a first layerof expanded polytetrafluoroethylene, which is magnified by a factor oftwenty (20×); and

FIG. 13 is a photomicrograph of a first second alternative embodimentwith a second layer of material that includes a bicomponent, spunbond,nonwoven material with embossed bond points that is thermobonded to afirst layer of expanded polytetrafluoroethylene, which is magnified by afactor of one hundred (100×).

DETAILED DESCRIPTION OF THE INVENTION

Referring now to FIG. 1, although a vacuum cleaner bag can be found inliterally any type of vacuum cleaner, one illustrative, but nonlimiting,type of vacuum cleaner is the upright style of vacuum cleaner that isgenerally indicated by numeral 10. The vacuum cleaner 10 draws in dirtand debris from flooring into a vacuum cleaner bag, which operates as afilter and is generally indicated by numeral 12.

Referring now to FIG. 2, an improved vacuum cleaner bag 12 of thepresent invention is formed of vacuum cleaner bag media that has a HighEfficiency Particulate Air (HEPA) rating of at least 99.97% efficiencyand is generally indicated by numeral 100. The vacuum cleaner bag media100 includes a first layer of material 120. The first layer of materialincludes an expanded polytetrafluoroethylene (ePTFE) membrane. Theweight of the expanded polytetrafluoroethylene (ePTFE) membrane can varytremendously.

There is also at least one second layer of material 140. Anillustrative, but nonlimiting, example of the preferred second layer ofmaterial 140 is a cellulose product, which incorporates additionaltextile fibers for strength and bonding. This is especially helpful whenthe second layer of material 140 is subject to damp conditions. Apreferred amount of additional textile fibers can range from about 10%to about 40% with a more preferred range from about 15% to about 30% andwith the most preferred range from about 15% to 20% of the second layerof material 140. The type of textile fibers that can be utilized tostrengthen the cellulose product can be of literally any type. Thesetextile fibers include but is not limited to: polyester; aramid;polypropylene; polyethylene; viscose rayon; and combinations thereof.

The preferred fiber for use in blending with the cellulose is abicomponent or hetrofil fiber that uses a core/sheath design. As shownon FIG. 4, a bicomponent fiber 170 includes both a sheath 174 as a firstcomponent and a core 172 as a second component. As an illustrative, butnonlimiting example, the sheath 174 can be made of polyethylene with afirst melting point, e.g., 130 degrees Celsius (266 degrees Fahrenheit)and the core 172 can be made of polyester with a second melting point,e.g., 255 degrees Celsius to 265 degrees Celsius (491 degrees Fahrenheitto 509 degrees Fahrenheit). The second melting point for polyesterdepends on the specific polyester polymer utilized. For processing on apaper machine, the fiber length and configuration is important since thefiber needs to be either relatively short, e.g., 625 millimeters (0.25inches), straight or crimpless for most paper making operations. Anexample of this type of textile fiber includes a Type 105 manufacturedby KoSa®, where KoSa® is a trademark of Arteva B. V., having a place ofbusiness at Leidsekade 98 1017 PP Amsterdam, Netherlands as well ashaving a place of business at 15710 JFK Boulevard, Houston, Tex. 77032.

The first layer of material 120 can be attached to at least one secondlayer of material 140 by any of wide variety of attachment processes.These attachments processes, as shown in FIG. 5, can includethermobonding. Thermobonding or lamination can involve infrared heat,hot gas and the preferred method that utilizes a hot roll laminatingmechanism that includes one heated roll and one water-cooled, nipcompression roll. Therefore, as shown in FIG. 5, a laminating operationis generally indicated by numeral 202. This includes a first roll 204 ofthe first layer of the ePTFE membrane 120 and a second roll 206 of thesecond layer of material 140. The first and second layers of material120 and 140 pass through laminating rolls, which are generally indicatedby numeral 207. This includes a lower, water-cooled, nip, compressionroll 210 and an upper, heated roll. The vertical position of the lower,water-cooled, nip, compression roll and an upper, heated roll 208 can bereversed. The preferred material for the upper, heated roll 208 includessteel. A typical pressure applied by the laminating rolls 207 betweenthe lower, water-cooled, nip, compression roll 210 and the upper, heatedroll 208 can preferably range from about 0 kilograms per linearmillimeter to about 8.93 kilograms per linear millimeter (0 pounds perlinear inch to about 500 pounds per linear inch) and more preferablyrange from about 1.43 kilograms per linear millimeter to about 2.14kilograms per linear millimeter (80 pounds per linear inch to about 120pounds per linear inch).

The speed of traverse can preferably range from about 3.05 meters to30.48 meters per minute (10 feet to about 100 feet per minute). Atypical example of a laminating operation 202 of this type is disclosedin U.S. Pat. No. 5,098,777, which issued to Koli on Mar. 24, 1992, whichis incorporated herein by reference. The application of speed,temperature and pressure in combination must generate heat that is abovethe first melting point for the second layer of material 140 and belowthe higher second melting point for the second layer of material 140.The first layer of material 120 can also be attached to the second layerof material 140 by adhesives. An example of this technology is disclosedin U.S. Pat. No. 5,902,843, which issued to Simon et al. on May 11,1999, which is incorporated herein by reference. The attachment of thefirst layer of material 120 to the second layer of material 140 can alsobe accomplished by the application of ultrasonic energy. An example ofthis technology is disclosed in U.S. Pat. No. 6,325,127, which issued toWaldrop on Dec. 4, 2001, which is incorporated herein by reference.

The traditional weight for a vacuum cleaner bag paper is approximately39 pounds (39 pounds per 3,000 square feet) or 0.044 kilograms persquare meter (1.85 ounces per square yard). Even with a fifteen percent(15%), a twenty percent (20%) or a thirty percent (30%) blend of fiberto cellulose material, a preferred thickness of 0.1524 millimeters(0.006 inches) with an air permeability of 0.71 cubic meters to 0.99cubic meters (25 cubic feet to 35 cubic feet) per minute was attainedprior to thermobonding or lamination. The preferred thickness of thevacuum bag media 100 can range from 0.0508 millimeters (0.002 inches) to0.508 millimeters (0.02 inches), however, a great deal of variation ispossible.

After thermobonding, as shown in Table 1, the following data forpressure drop (resistance) and filtration efficiency in relationship toair flow at 5.33 cm./sec. (10.49 feet/minute) is obtained andgraphically illustrated on FIGS. 7 and 8, respectively. The pressuredrop (resistance) was about 40 millimeters (1.57 inches) with the airpermeability in the range between 0.113 cubic meters (4.0 cubic feet) to0.156 cubic meters (5.5 cubic feet) per minute at 0.5 inches of waterpressure differential.

TABLE 1 Efficiency Pressure Drop (millimeters) Pressure Drop (inches)99.999 41.65 1.64 99.9996 43.52 1.71 99.9997 44.26 1.74 99.993 39.231.55 99.999 39.49 1.56 99.994 38.86 1.53 99.9996 46.53 1.83 99.995 43.831.73 99.9999 42.05 1.66 99.9998 42.97 1.69 99.9998 43.18 1.70 99.99744.27 1.74 99.998 38.12 1.50 99.999 36.71 1.45 99.993 39.54 1.56 99.99638.72 1.52 99.994 38.77 1.63 99.996 39.66 1.56 99.996 39.83 1.57 99.99941.86 1.65 99.998 42.8 1.69 99.999 42.28 1.67 99.9994 40.42 1.59 99.999440.01 1.58 99.985 41.15 1.62 99.998 41.16 1.62 99.996 42.23 1.66 99.99639.67 1.56 99.998 38.49 1.52 99.992 38.57 1.52 99.999 40.63 1.60 99.99641.13 1.62 99.9991 40.49 1.59 99.9996 39.99 1.57 99.998 41.55 1.6499.998 43.95 1.73 99.9996 35.88 1.41 99.998 37.68 1.48 99.999 41.55 1.6499.995 38.13 1.50

As shown in Table 2, the following data for pressure drop (resistance)and filtration efficiency in relationship to air flow at 8.54 cm./sec.(16.81 feet/minute), which is the flow rate found in the typical vacuumcleaner 10, is obtained and graphically illustrated on FIGS. 7 and 8,respectively.

TABLE 2 Efficiency Pressure Drop (millimeters) Pressure Drop (inches)99.989 56.42 2.22 99.989 50.94 2.00 99.99 52.48 2.07 99.996 58.77 2.3199.994 53.7 2.11 99.997 53.63 2.11 99.997 61.24 2.41 99.993 59.28 2.3399.991 61.92 2.44 99.9996 63.78 2.51 99.999 62.62 2.47 99.996 62.28 2.4599.99 61.51 2.42 99.996 60.92 2.40 99.998 62.65 2.47 99.996 59.76 2.3599.994 59.89 2.36 99.996 66.02 2.60 99.997 64.21 2.53 99.993 60.59 2.39

Therefore, the HEPA efficiency rating of 99.97% efficiency was easilyobtained. A photomicrograph of the cellulose product utilizingbicomponent fibers that has been magnified five hundred times (500×) isillustrated on FIG. 9. Due to the low adhesion properties and excellentrelease properties of the vacuum cleaner bag media 100, allows dust tosettle in the bottom of the vacuum cleaner bag 12, as shown in FIG. 1,with a minimal increase in resistance. This improves the performance ofthe vacuum cleaner 10.

A first alternative embodiment, of the second layer of material 140includes a bicomponent, spunbond, nonwoven material as shown in FIG. 2.An illustrative, but nonlimiting, example of this type of bicomponent,spunbond, nonwoven material includes a polyester/polyethylene basedhetrofil fiber filament. One type of polyester/polyethylene basedhetrofil fiber filament includes the ELEVES™ spunbond product lineproduced by UNITIKA®. UNITIKA® is a federally registered trademark ofUnitika Kabushiki Kaisha d.b.a. Unitika Ltd., having a place of businessat 1-50, Higashi-Hon-Machi Amagasaki-Shi, Hyogo-ken, Japan. Theconstruction of this bicomponent fiber is a core and sheath design thatis generally indicated by numeral 170 on FIG. 4, where the ratio of thecore 172, as a second component, to the sheath 174, as a firstcomponent, can range from 80% core 172 to 20% sheath 174 to 20% core 172to 80% sheath 174 with the preferred value being 50% core 172 to 50%sheath 174. The polymer forming the core 172 preferably has a highermelting point than the polymer fonning the sheath: 174. Oneillustrative, but nonlimiting, example of polymer that can be utilizedfor the core 172 is polyester and one illustrative, but nonlimitingexample, of the polymer that can be utilized for the sheath 174 ispolyethylene. There is a difference in the melting point for the polymerused for the core 172 and the polymer used for the sheath 174 with thesheath 174 being at a first melting point and the core 172 being at asecond melting point that is higher than the first melting point. Forexample, the melting point for polyester is 255 degrees Celsius to 265degrees Celsius (491 degrees Fahrenheit to 509 degrees Fahrenheit) andthe melting point for polyethylene is 130 degrees Celsius (266 degreesFahrenheit).

The ePTFE membrane 120 that is utilized on the filtration side of thevacuum cleaner bag 12 is regenerable in use due to the low adhesion andexcellent release properties. A major advantage of this presentinvention is the flexibility of this second layer of material 140, whichallows this material to fold readily and crease easily to conform to thedifferent shapes required for the vacuum cleaning bag 12, as shown onFIG. 1. Moreover, the thermoplastic qualities of this second layer ofmaterial 140 allows for thermobonding, i.e., heat welding, as opposed toutilizing adhesives during the construction of the vacuum cleaner bag12. Heat welding generally provides a seal that is more impermeable andcleaner than a seal formed by adhesives. In addition, heat welding isgenerally less expensive than the application of adhesives.

The flexibility of the bicomponent, spunbond, nonwoven material thatforms the second layer of material 140 is derived from a consolidatedprocess since spunbond media is traditionally consolidated by smoothcalender rolls. Due to the fact that the bicomponent, spunbond, nonwovenmaterial is thermally consolidated, an increased level of stiffness willresult since most of the lower melting point polymers (first componentsor sheaths 174) will melt. Therefore, as shown in FIG. 6, there is anupper calender roll 302 and a lower calender roll 304. Preferably, atleast one of the calender rolls 302, 304 is embossed with protrusions306. This provides for the melting of only a select portion of the firstcomponent having the lower melting point. This can range from about 5%to about 40%, and preferably can range from about 15% to about 25% andmost preferably can range from about 18% to about 20%. An example ofthis second layer of material 140 that is selectively melted is found onthe FIG. 10 by a series of bond points. All of the lower melting point(first component or sheath 174) material within the bond points 310 willmelt. FIGS. 10 and 11 are photomicrographs of the bicomponent, spunbond,nonwoven material, where the bicomponent, spunbond, nonwoven materialhas been magnified twenty times (20×) and one thousand times (1,000×),respectively. This embossed spunbond material forming this second layerof material 140 has a higher air permeability than. flat bonded media ofthe same basis weight and fiber denier. A typical example of a calenderof this type for forming nonwoven fabric includes that disclosed in U.S.Pat. No. 4,605,366, which issued to Lehmann et al. on Aug. 12, 1986,which is incorporated herein by reference.

The first layer of material 120 can be attached to at least one secondlayer of material 140 by any of wide variety of attachment processes.These attachment processes, as shown in FIG. 5, can includethermobonding. Thermobonding or lamination can involve infrared heat,hot gas and the preferred method that utilizes a hot roll laminatingmechanism that includes one heated roll and one water-cooled, nipcompression roll. Therefore, as shown in FIG. 5, a laminating operationis generally indicated by numeral 202. This includes a first roll 204 ofthe first layer of the ePTFE membrane 120 and a second roll 206 of thesecond layer of material 140. The first and second layers of material120 and 140 pass through laminating rolls, which are generally indicatedby numeral 207. This includes a lower, water-cooled, nip, compressionroll 210 and an upper, heated roll 208. The vertical position of thelower, water-cooled, nip, compression roll 210 and an upper, heated roll208 can be reversed. The preferred material for the upper, heated roll208 includes steel. A typical pressure applied by the laminating rolls207 between the lower, water-cooled, nip, compression roll 210 and theupper, heated roll 208 can preferably range from about 0 kilograms perlinear millimeter to about 8.93 kilograms per linear millimeter (0pounds per linear inch to about 500 pounds per linear inch) and morepreferably range from about 1.43 kilograms per linear millimeter toabout 2.14 kilograms per linear millimeter (80 pounds per linear inch toabout 120 pounds per linear inch).

The speed of traverse can preferably range from about 3.05 meters to30.48 meters per minute (10 feet to about 100 feet per minute). Atypical example of a laminating operation 202 of this type is disclosedin U.S. Pat. No. 5,098,777, which issued to Koli on Mar. 24, 1992, whichis incorporated herein by reference. The application of speed,temperature and pressure in combination must generate heat that is abovethe first melting point for the second layer of material 140 and belowthe higher second melting point for the second-layer of material 140.The first layer of material 120 can also be attached to the second layerof material 140 by adhesives. An example of this technology is disclosedin U.S. Pat. No. 5,902,843, which issued to Simon et al. on May 11,1999, which is incorporated herein by reference. The attachment of thefirst layer of material 120 to the second layer of material 140 can alsobe accomplished by the application of ultrasonic energy. An example ofthis technology is disclosed in U.S. Pat. No. 6,325,127, which issued toWaldrop on Dec. 4, 2001, which is incorporated herein by reference.

Testing of the airflow in which the challenge aerosol is presented tothe media is at 5.33 cm./sec. (10.55 ft./min) and was performed with aDioctyl Phthalate (DOP) aerosol on a TSI 8160 testing device with a 0.3micron (11.81 microinch) particle size for one hundred percent (100%) ofthe particles. The pressure drop (resistance) was between 30 millimetersto 40 millimeters (1.18 inches to 1.58 inches). The air permeabilitynormally ranges between about 0.113 cubic meter (4 cubic feet) perminute to about 0.227 cubic meters (8 cubic feet) per minute at a 12.7millimeter (0.5 inch) water pressure differential. The HEPA efficiencyrating surpassed 99.97%. FIGS. 12 and 13 are photomicrographs of thebicomponent, spunbond, nonwoven material of the second layer of material140 that has been thermobonded to the first layer of ePTFE membranematerial 120, which has been magnified by a factor of twenty (20×) andone hundred (100×), respectively. The preferred, but nonlimiting, weightof the second layer of material 140, prior to thermobonding, can rangefrom about 11.85 grams per square meter (0.5 ounces per square yard) toabout 142.2 grams per square meter (6 ounces per square yard) with anoptimal value of 47.4 grams per square meter (2 ounces per square yard).

A second alternative embodiment, of the second layer of material 140includes a bicomponent, carded, thermal bonded, nonwoven material asshown in FIG. 2. Therefore, theoretically but not necessarily, allfibers could be of the same type and size. This material processprovides for a customization of the properties to maximize air flow andminimize the increase in pressure drop, which is otherwise known asresistance. There are a myriad of core and sheath bicomponent fibersthat can be utilized to create the blended, thermial bond, nonwovenmaterial 140. This includes virtually any type of polymer fiber. Thisincludes a first component, e.g., polymer, having a first melting pointand a second component, e.g., polymer, having a higher melting pointthat is higher than the first melting point. Examples of these types offibers that have differing melting points include polyester,polypropylene, polyethylene, nylon and mixtures thereof, among others,as well as the same type of polymer with different melting points suchas polyester.

The bicomponent fibers can range from about 5% to about 40%, andpreferably can range from about 15% to about 25% and most preferably canrange from about 18% to about 20% of the second layer of material 140.The remaining fiber can be of another type of fiber, e.g., polymerfiber. An illustrative, but nonlimiting, example of another polymercould include polyester fibers. This other polymer would have a highermelting point than the first or lower melting point. An illustrative,but nonlimiting, example would include 20% bicomponent,polyester/polypropylene fibers and 80% standard polyester fiber. Asshown in FIG. 4, an example of this type of bicomponent fiber 170includes a polyester core 172 and a polyethylene sheath 174 such as Type225 manufactured by KoSa®, where KoSa® is a trademark of Arteva B.V.,having a place of business at Leidsekade 98 1017 PP Amsterdam,Netherlands as well as having a place of business at 15710 JFKBoulevard, Houston, Tex. 77032. In this illustrative, but nonlimiting,example, a 67.75 grams/ square meter (2.0 oz./sq. yd.) media isproduced. A supplier that can produce this media through carding andthermal bonding is Bondex Inc., having a place of business at 2 MaxwellDrive, Trenton, S.C. 29847.

The flexibility of the bicomponent, thermal bond, nonwoven material thatforms the second layer of material 140 is derived from a consolidatedprocess since thermal bond nonwoven media is traditionally consolidatedby smooth calender rolls. Due to the fact that the bicomponent, thermalbond, nonwoven material is thermally consolidated, an increased level ofstiffness will result since most of the lower melting point fibers willmelt. However, since there are fibers other than the bicomponent fibers170 present in this second alternative embodiment, greater air flowresults since a much lower percentage of the fibers will melt. Thissecond alternative embodiment is superior to the first alternativeembodiment since the ratio of bicomponent fibers 170 to other fibersthat have a higher melting point can be selected to achieve a desiredair flow. As shown in FIG. 6, the bicomponent, thermal bond, nonwovenmaterial is processed with an upper calender roll 302 and a lowercalender roll 304. Preferably, at least one of the calender rolls 302,304 is embossed with protrusions 306. This provides for the melting ofonly a select portion of the first component material having the lowermelting point that is present at the protrusions 306. This can rangefrom about 5% to about 40%, and preferably can range from about 15% toabout 25% and most preferably can range from about 18% to about 20% ofthe first component. A typical example of a calender of this type forforming nonwoven fabric includes that disclosed in U.S. Pat. No.4,605,366, which issued to Lehmann et al. on Aug. 12, 1986., which isincorporated herein by reference. Due to the nature of this bicomponent,thermal bonded, nonwoven material forming the second layer of material140, ill the preferred illustrative, but nonlimiting embodiment, thereare approximately twenty percent (20%) less bonding sites in comparisonof the spun bond, nonwoven material in the first alternative embodiment.This provides for less of the first layer of ePTFE material 120 frombeing melted and blocked, which results in greater airflow and morefiltration.

The first layer of material 120 can be attached to at least one secondlayer of material 140 by any of wide variety of attachment processes.These attachment processes, as shown in FIG. 5, can includethermobonding. Thermobonding or lamination can involve infrared heat,hot gas and the preferred method that utilizes a hot roll laminatingmechanism that includes one heated roll and one water-cooled, nipcompression roll. Therefore, as shown in FIG. 5, a laminating operationis generally indicated by numeral 202. This includes a first roll 204 ofthe first layer of the ePTFE membrane 120 and a second roll 206 of thesecond layer of material 140. The first and second layers of material120 and 140 pass through laminating rolls, which are generally indicatedby numeral 207. This includes a lower, water-cooled, nip, compressionroll 210 and an upper, heated roll 208. The vertical position of thelower, water-cooled, nip, compression roll and an upper, heated roll 208can be reversed. The preferred material for the upper, heated roll 208includes steel. A typical pressure applied by the laminating rolls 207between the lower, water-cooled, nip, compression roll 210 and theupper, heated roll 208 can preferably range from about 0 kilograms perlinear millimeter to about 8.93 kilograms per linear millimeter (0pounds per linear inch to about 500 pounds per linear inch) and morepreferably range from about 1.43 kilograms per linear millimeter toabout 2.14 kilograms per linear millimeter (80 pounds per linear inch toabout 120 pounds per linear inch).

The speed of traverse can preferably range from about 3.05 meters to30.48 meters per minute (10 feet to about 100 feet per minute). Atypical example of a laminating operation 202 of this type is disclosedin U.S. Pat. No. 5,098,777, which issued to Koli on Mar. 24, 1992, whichis incorporated herein by reference. The application of speed,temperature and pressure in combination must generate heat that is abovethe first melting point for the second layer of material 140 and belowthe higher second melting point for the second layer of material 140.The first layer of material 120 can also be attached to the second layerof material 140 by adhesives. An example of this technology is disclosedin U.S. Pat. No. 5,902,843, which issued to Simon et al. on May 11,1999, which is incorporated herein by reference. The attachment of thefirst layer of material 120 to the second layer of material 140 can alsobe accomplished by the application of ultrasonic energy. An example ofthis technology is disclosed in U.S. Pat. No. 6,325,127, which issued toWaldrop on Dec. 4, 2001, which is incorporated herein by reference.

Testing of the airflow in which the challenge aerosol is presented tothe vacuum bag media 100 is at 5.33 cm./sec. (10.55 ft./min) and wasperformed with a Dioctyl Phthalate (DOP) aerosol on a TSI 8160 testingdevice with a 0.3 micron (11.81 microinch) particle size for one hundredpercent (100%) of the particles. The pressure drop (resistance) wasbetween 20 millimeters to 28 millimeters (0.787 inches to 1.10 inches).The air permeability normally ranges between about 0.141 cubic meter (5cubic feet) per minute to about 0.255 cubic meter (9 cubic feet) perminute at a 12.7 millimeter (0.5 inch) water pressure differential. TheHEPA efficiency rating surpassed 99.97%. The weight of the second layerof material 140, prior to thermobonding, can preferably range from about11.85 grams per square meter (0.5 ounces per square yard) to about 142.2grams per square meter (6 ounces per square yard) with a preferred valueof 47.4 grams per square meter (2 ounces per square yard).

A third alternative embodiment includes a third layer of material 160 inaddition to the second layer of material 140. This third layer ofmaterial 160 can include a wide variety of textile material and fabric,as shown in FIG. 3. As previously described above, the second layer ofmaterial can include cellulose material, spunbond, nonwoven material andfiber blended, thermal bonded nonwoven material. The third layer ofmaterial 160 is typically very light weight and in a preferred rangefrom about 9.48 grams per square meter (0.4 ounces per square yard) toabout 23.70 grams per square meter (1.0 ounces per square yard). Thisthird layer of material 160 is very open fabric that provides a highdegree of air flow. This third layer of material 160 is designed toprotect the first layer of material 120 from projectiles within thevacuum cleaner bag 12 that have been suctioned by the vacuum cleaner. Inaddition, abrasion can also be caused by metal formers, feed rolls andguide plates during the manufacturing process. This damage to the firstlayer of ePTFE material 120 can result in less than HEPA efficiency.This third layer of material 160 can provide the structural integrity tothe vacuum bag media 100 while preserving a HEPA efficiency rating. thatsurpasses 99.97%. This third layer of material 160 can be attached tothe other side of the first layer of material 120 in the same manner asthe second layer of material 140, as previously described above.

An illustrative, but nonlimiting, example of this type of fabric caninclude, but is not limited to, a thermal bonded nonwoven produced byPGI Nonwovens, having a place of business at 10 Panasonic Way,Mooresville, N.C. 28115. This technology utilizes carded, dry laidtechnology with a flat bond finish.

Although the preferred embodiment of the present invention and themethod of using the same has been described in the foregoingspecification with considerable details, it is to be understood thatmodifications may be made to the invention which do not exceed the scopeof the appended claims and modified forms of the present invention doneby others skilled in the art to which the invention pertains will beconsidered infringements of this invention when those modified formsfall within the claimed scope of this invention.

1. A vacuum bag media comprising: a first layer that includes anexpanded polytetrafluoroethylene membrane; at least one second layer,having a first side and a second side, and comprising a first materialand a second material, said first material comprising a plurality ofbicomponent fibers comprising a first portion having a first meltingpoint and a second portion having a second melting point that is higherthan the first melting point, wherein the first material is in contactwith said first layer and said second material of the second layer, thefirst portion of the bicomponent fibers is melted to attach the firstlayer to the first side of the at least one second layer; and a thirdlayer comprising a third material having a third melting point that ishigher than the first melting point, said third material selected fromthe group consisting of textile material and fabric, said third layerattached to the second side of the at least one second layer or saidfirst layer.
 2. The vacuum bag media according to claim 1, wherein thesecond material includes a fiber selected from the group consisting ofcellulose, polyester, aramid, polypropylene, polyethylene, viscose rayonand combinations thereof.
 3. The vacuum bag media according to claim 1,wherein the at least one second layer includes a spunbond, nonwovenfabric.
 4. The vacuum bag media according to claim 1, wherein the atleast one second layer includes a thermal bond, nonwoven fabric.
 5. Thevacuum bag media according to claim 1, wherein the first portionincludes at least one fiber sheath and the second portion includes atleast one fiber core.
 6. The vacuum bag media according to claim 5,wherein at least 10% of the first portion includes the at least onefiber sheath.
 7. The vacuum bag media according to claim 1, wherein thefirst portion includes polyethylene and the second portion includespolyester.
 8. The vacuum bag media according to claim 1, wherein thefirst portion is selected from the group consisting of polyester,polypropylene, polyethylene, nylon and mixtures thereof and the secondportion is selected from the group consisting of polyester,polypropylene, polyethylene, nylon and mixtures thereof.
 9. A vacuum bagcomprising a closed receptacle for collecting dirt particles and havingan inlet opening for allowing a dirt laden airstream to enter, saidreceptacle formed from a composite sheet comprised of at least one layerof expanded polytetraflouroethylene and at least one substrate layer,said at least one substrate layer comprising a first material and asecond material, said first material comprising a plurality ofbicomponent fibers with a first portion having a first melting point anda second portion having a second melting point that is higher than thefirst melting point, said second material having a third melting pointthat is higher than the first melting point, wherein the first materialand the second material are blended together and the first portion ofthe bicomponent fibers is at least partially melted to attach said atleast one layer of expanded polytetraflouroethylene to said at least onesubstrate layer.
 10. The vacuum bag of claim 9, wherein said closedreceptacle is air permeable and has at least a HEPA filtration rating.11. The vacuum bag of claim 9, wherein the at least one substrate layerincludes bicomponent fibers in a range from about 5% to about 40% byweight of the at least one substrate layer.
 12. A vacuum bag mediacomprising: a first layer that includes an expandedpolytetrafluoroethylene membrane for surface filtration; and at leastone second layer, having a first side and a second side, and comprisinga first material and a second material, said first material comprising aplurality of bicomponent fibers comprising a first portion having afirst melting point and a second portion having a second melting pointthat is higher than the first melting point, wherein the first materialis in contact with said first layer and a said second material of thesecond layer, and the first portion of the bicomponent fibers is meltedto attach the first layer to the first side of the at least one secondlayer.
 13. The vacuum bag media according to claim 12, wherein thesecond material includes a fiber selected from the group consisting ofcellulose, polyester, aramid, polypropylene, polyethylene, viscose rayonand combinations thereof.
 14. The vacuum bag media according to claim12, wherein the at least one second layer includes a spunbond, nonwovenfabric.
 15. The vacuum bag media according to claim 12, wherein the atleast one second layer includes a thermal bond, nonwoven fabric.
 16. Thevacuum bag media according to claim 12, wherein the first portionincludes at least one fiber sheath and the second portion includes atleast one fiber core.
 17. The vacuum bag media according to claim 16,wherein at least 10% of the first portion includes the at least onefiber sheath.
 18. The vacuum bag media according to claim 12, whereinthe first portion includes polyethylene and the second portion includespolyester.
 19. The vacuum bag media according to claim 12, wherein thefirst portion is selected from the group consisting of polyester,polypropylene, polyethylene, nylon and mixtures thereof and the secondportion is selected from the group consisting of polyester,polypropylene, polyethylene, nylon and mixtures thereof.